The present invention is related to an improved steel cable lock structure in which the lock bolts and relevant driving structure are rotatable relative to the casing and lock core so as to avoid damage of the lock bolts or the lock bolt hole of the locked article due to twisting force applied to the casing.
Taiwanese Patent Publication Nos. 370147, 413259, 424840, 435561, 435725 and U.S. Pat. No. 5,502,989 disclose various steel cable lock structures. These steel cable lock structures can be substantially divided into several kinds as follows:
1. A fixed lock bolt is disposed on the casing in cooperation with a movable lock bolt. The movable lock bolt can be extended from the fixed lock bolt and engaged in a hole formed on an article to achieve a locking effect (such as Taiwanese Publication Nos. 370147 and 424840).
2. Two relatively movable lock bolts (lock plates) can be expanded to engage in a hole formed on an article to be locked so as to achieve a locking effect (such as Taiwanese Publication Nos. 413259 and 435561 and an embodiment of U.S. Pat. No. 5,502,989).
3. The rear end of the lock casing is formed with an axially projecting latch block. The lateral faces of the latch block are formed with slide channels. Two corresponding corners of the latch block are formed with latch projections for engaging with inner wall face of the computer housing. A pin fitted with a restoring spring is extensible/retractable in the slide channels of the latch block. When a lock bolt is inserted into a preset hole, the pin is moved out to make the latch block deflect by a certain angle to engage with inner side of the hole (such as Taiwanese Publication No. 435724).
4. One end of a lock bolt is formed with an elongated transversely extending stop bar. The lock bolt is pivotally extended into a slot preformed on an article to be locked. By means of rotating the lock bolt, the stop bar is rotated by a certain angle to intersect the slot to achieve a locking effect (such as an embodiment of U.S. Pat. No. 5,502,989).
The above lock structures have a common characteristic, that is, the lock bolt has a certain strength against an external force applied onto the lock bolts to draw the lock bolts out of the hole of the article. However, the fixed lock bolt and movable lock bolt (or two movable lock bolts) are separately arranged. In the case the lock body is forcedly turned, the lock bolts tend to be permanently twisted and deformed. As a result, the lock bolt will lose its locking effect and can be easily drawn out of the hole of the article. Even if the material of the lock bolt is reinforced or the shape of the lock bolt is such designed as to increase the torque strength of the lock bolt, the hole of the article will be eventually damaged to lose the locking effect. Moreover, the change of material or design of shape will lead to increased cost for material and increased manufacturing cost.
It is therefore a primary object of the present invention to provide an improved steel cable lock structure. An inner stop member is relatively rotatably fitted with one end of the lock casing. A core shaft extendably/retractably extends through the center of the inner stop member. An outward extending end of the core shaft is formed with an expansion section. A front cap is cooperatively fitted with the inner stop member to restrict at least one lock bolt pivotally rotatable relative to the front cap. The outer ends of the lock bolts are formed with outward extending hook sections. The core shaft can extend or retract to deflect the lock bolts. Accordingly, the hook sections of the lock bolts can expand to lock a lock bolt hole of an article or contract to unlock the lock bolt hole. The lock casing and the inner stop member are rotatable relative to each other so as to avoid damage of the lock bolts or the lock bolt hole of the locked article due to twisting force applied to the casing.
It is a further object of the present invention to provide the above steel cable lock structure in which the lock bolts are formed with guide channels on inner opposite faces. The circumference of the core shaft is formed with axially extending lateral ribs which can at least partially extend into the guide channels to connect the lock bolts with the core shaft. The strengths of the lock bolts and the core shaft are combined to enhance torque strength of the lock bolt structure so as to avoid damage of the lock bolts or the lock bolt hole of the locked article due to twisting force applied to the casing.